Final answer:
The factored form of x^2 + 13x + 42 is (x+6)(x+7).
Step-by-step explanation:
The factored form of the quadratic expression x^2 + 13x + 42 can be found by factoring the expression into two binomial terms. First, we need to find two numbers that multiply to give the constant term (42) and add up to give the coefficient of the middle term (13). In this case, the numbers are 6 and 7. So, the factored form is (x + 6)(x + 7). Therefore, the correct answer is a) (x+6)(x+7).